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New Member

When to use FR static map in ospf?

I wan puzzled by the the question that when I must to use 'frame-rely map ip x.x.x.x dlci broadcast' command.

Dose reverse-arp tell me the dynamic mapping if I use partion mesh FR network and if I close reverse-arp,will I must set static map for each remote ospf router not directly connected? (Does it ralated to the 'ip ospf network'command?)

Thanks

  • Other Network Infrastructure Subjects
2 REPLIES
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Re: When to use FR static map in ospf?

Typically, you only use the frame relay map command when you are configuring a multipoint frame realy interfaces. This tells the router which dlci to map to which remote ip address on what appears to be a broadcast interface (from the hub router's perspective). I've never seen aframe multipoint work with arp or reverse arp (again, the hub router thinks it's a broadcast segment, but each spoke thinks it's a point-to-point).

This doesn't relate to the ospf network command in any way. There are a number of ways you can run ospf over a frame multipoint network:

-- Create point-to-point subinterfaces, which will use more ip address space, but will make fast don detection possible, and make troubleshooting easier.

-- Use a single multipoint interface with the ip ospf network-type point-to-multipoint, which is simple to configure, and reduces the ip address space outlay, but it injects a lot of /32's into your ospf tables, which can impact convergence, etc.

-- Use a single multipoint interface with the ip ospf network-type broadcast command. Set each remote with an ospfpriority of 0, so only the hub can become the dr.

-- Use a single multipoint interface with the ip ospf network-type nonbroadcast, and then configure each remote router as a neighbor manually.

Which one of these you use is going to depend on which downside you like the best. :-)

Russ.W

New Member

Re: When to use FR static map in ospf?

Can I think that the frame-relay inverse-arp can get the DLCI-IP mapping cross a hub ?(no vc directly connect btw spokens)

So if I stop the FR inverse-arp,must I indicate hub and all other spokens at the sopken router? )

such as:

spoken1(config-if)#frame-relay map ip hub 100 broadcast

spoken1(config-if)#frame-relay map ip spoken2 100 broadcast

spoken1(config-if)#frame-relay map ip spoken3 100 broadcast

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